In electrical communication systems information often is transmitted over a binary channel by use of a series of binary digits such as 0's and 1's. Often, the bit stream in the channel is distorted by transients from a bit interval extending into one or more subsequent bit intervals. Such distortion is known as intersymbol interference (ISI). As a result of such intersymbol interference, the channel output may substantially comprise an analog waveform rather than a binary bit stream.
The amount of ISI is dependent upon the channel bandwidth; the channel bandwidth sets the upper limit on the bit rate that can be transmitted through the channel. In a linear, or substantially linear, binary channel, the bit error rate is determined by the channel signal-to-noise ratio and the channel bandwidth. In practice, the maximum bit rate that can be employed is highly dependent upon the method and means used to detect the distorted binary digits at the channel output. The present invention is directed to method and apparatus for regenerating the distorted binary signal stream.
The binary signal regeneration method and apparatus of the present invention is not limited to any particular application. The invention is useable, for example, in binary communications systems for transmission of digitized text, graphics, audio and/or video signals. For example, the invention is well adapted for interconnection of computers in, say, computer networks. It may be used in repeater stations included in binary signal transmission systems. Another use includes the regeneration of digital signals that have been subjected to magnetic recording and playback, such as those from a magnetic storage disk employed in a computer. In this application, the channel includes magnetic recording and playback means. As will become apparent, the invention is not limited to such uses.